April 21, 2021, 05:02:33 posle podne
Dobrodošli, Gost. Molim vas prijavite se ili se registrujte. Da niste izgubili svoj aktivacioni mejl?
413.713 poruka u 18.377 tema - 20.261 članova - Poslednji član: Raigor
X3MShop banner

Autor Tema: Science news for health and building lean muscle - monthly update  (Pročitano 41483 puta)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Science news for health and building lean muscle - monthly update
« poslato: Novembar 06, 2009, 02:21:20 posle podne »
Fat Burning Zone vs. Aerobic Zone Differences in Training

You’ve probably heard that there’s a fat-burning zone for cardio workouts, right?  In fact, some machines even indicate a specific heart rate target to burn the most fat.  But are they right?  Is that the best place to target?  What about improving aerobic capacity?  Since it’s important to train for aerobic fitness too, does that mean you need to train twice, once in each zone?

Well, researchers at University of St. Thomas in Minnesota took 36 runners and did some detailed analysis of heart rates and fat oxidation vs. VO2 max (maximal oxygen uptake, a measure of aerobic fitness).  Here’s what they found:

The best fat burning zone was at about 68% to 87% of maximal heart rate, while the best aerobic zone was between 59% and 76%.  Note the big overlap.  Translation:  you can simultaneously optimize fat burn and aerobic fitness by targeting between 68% and 76%.

If you dig deeper, there are two other points worth noting:  a) the difference in fat calories burned can differ by a factor of 2 or so; this means there really is a fat-burning zone, and b) there is a high variability from individual to individual so you can’t just assume these averages apply to everyone; you’ll need to do some testing on yourself to see which range is best.

This comes from Journal of Strength and Conditioning Research 23(7): p2090-2095 (2009).

------------------------------------------------------

Skip The Leucine And Save Your Money

The University Of Texas released the findings of a study comparing the anabolic (muscle growth) effects of leucine added to a whey protein drink versus jus the whey protein drink.  The timing was following a high intensity lower body workout.  Turns out, there was no difference.  So if you are paying extra for protein powder enhanced with leucine, save your money and just buy good old whey protein.

Applied Physiology and Nutrition Metabolism, 34: 151-161, 2009.

------------------------------------------------------


Exercise keeps dangerous visceral fat away a year after weight loss finds UAB study
Published: Thursday, October 29, 2009 - 11:00 in Health & Medicine

A study conducted by exercise physiologists in the University of Alabama at Birmingham (UAB) Department of Human Studies finds that as little as 80 minutes a week of aerobic or resistance training helps not only to prevent weight gain, but also to inhibit a regain of harmful visceral fat one year after weight loss. The study was published online Oct. 8 and will appear in a future print edition of the journal Obesity.

Unlike subcutaneous fat that lies just under the skin and is noticeable, visceral fat lies in the abdominal cavity under the abdominal muscle. Visceral fat is more dangerous than subcutaneous fat because it often surrounds vital organs. The more visceral fat one has, the greater is the chance of developing Type 2 diabetes and heart disease.

In the study, UAB exercise physiologist Gary Hunter, Ph.D., and his team randomly assigned 45 European-American and 52 African-American women to three groups: aerobic training, resistance training or no exercise. All of the participants were placed on an 800 calorie-a-day diet and lost an average 24 pounds. Researchers then measured total fat, abdominal subcutaneous fat and visceral fat for each participant.

Afterward, participants in the two exercise groups were asked to continue exercising 40 minutes twice a week for one year. After a year, the study's participants were divided into five groups: those who maintained aerobic exercise training, those who stopped aerobic training, those who maintained their resistance training, those who stopped resistance training and those who were never placed on an exercise regimen.

"What we found was that those who continued exercising, despite modest weight regains, regained zero percent visceral fat a year after they lost the weight," Hunter said. "But those who stopped exercising, and those who weren't put on any exercise regimen at all, averaged about a 33 percent increase in visceral fat.

"Because other studies have reported that much longer training durations of 60 minutes a day are necessary to prevent weight regain, it's not too surprising that weight regain was not totally prevented in this study," Hunter said. "It's encouraging, however, that this relatively small amount of exercise was sufficient to prevent visceral fat gain."

The study also found that exercise was equally effective for both races.
« Poslednja izmena: Novembar 12, 2009, 10:55:58 posle podne The_Bulldog »

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science new's for health and building lean muscle - monthly update
« Odgovor #1 poslato: Novembar 11, 2009, 01:33:58 pre podne »
Moderately Reduced Carbohydrate Diet Keeps People Feeling Full Longer


-A modest reduction in the amount of carbohydrates eaten, without calorie restriction and weight loss, appears to increase a sense of fullness, which may help people eat less, a preliminary study found. The results were presented at The Endocrine Society's 91st Annual Meeting in Washington, D.C.

"There has been great public interest in low-carbohydrate diets for weight loss, but they are difficult to maintain, in part because of the drastic reduction in carbohydrates," said coauthor Barbara Gower, PhD, a professor in the Department of Nutrition Sciences, University of Alabama at Birmingham.

In this study funded by the National Institutes of Health, Gower and her co-workers investigated whether a modest reduction in dietary carbohydrates, or "carbs," would improve feelings of fullness better than a carbohydrate level comparable to that of the typical U.S. diet.

In a standard American diet, according to Gower, 55 percent of daily calories consumed come from carbohydrates: sugars, starches and fiber. The control diet used in their study contained 55 percent of daily calories from carbohydrates, in contrast to their "moderate-carb diet" which was 43 percent of calories from carbohydrates. The moderate-carb diet had more fat than their control diet—39 percent versus 27 percent of calories—so that protein intake could be the same percentage. The researchers matched the protein intake of both diets studied (18 percent of calories) because protein may influence both satiety ("fullness") and insulin secretion.

The authors assigned the moderate-carb diet to 16 adults and the standard diet to 14 adults for a month. Subjects received enough calories to maintain their weight at what it was before the study. During the study they were weighed each weekday, and if a participant gained or lost weight, the amount of food was modified individually so weight could stay the same. After the subjects adjusted to their diet for 4 weeks, they ate a test meal, a breakfast that was specific to their diet.

When carbs are eaten and digested, they change into sugar. Before and after the meal, the researchers measured the subjects' levels of insulin and circulating glucose (nonfasting blood sugar) and asked them to rate their hunger or fullness. They evaluated insulin response to a meal and blood sugar levels, because lower insulin and stable blood sugar levels may contribute to increased feelings of fullness, Gower explained.

Their research showed that, even in the absence of weight loss, a modest reduction in dietary carbohydrates was sufficient to lower insulin and stabilize blood sugar after a meal. Ratings of fullness were higher in the group on the moderate-carb diet before eating breakfast and stayed higher for a longer time after the meal, compared with those eating the standard diet.

"Over the long run a sustained modest reduction in carbohydrate intake may help to reduce energy consumption and facilitate weight loss," Gower said.

Paula Chandler-Laney, PhD, of the University of Alabama at Birmingham presented the study results.

ScienceDaily (June 12, 2009)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science new's for health and building lean muscle - monthly update
« Odgovor #2 poslato: Novembar 11, 2009, 01:48:59 pre podne »
Exercise Therapy Best For Knee Pain, Study Finds



For patients with severe knee pain, supervised exercise therapy is more effective at reducing pain and improving function than usual care, finds a study published on bmj.com.

Patellofemoral pain syndrome is a condition in which pain occurs at the front of the knee during or after exercise and is a common reason to visit the doctor. Women are more likely to be affected than men, and symptoms usually start during adolescence when participation in sporting activities is high.

General advice is to rest during periods of pain and to avoid pain provoking activities. This "wait and see" approach is considered usual care.

A recent study reported only limited evidence for the effectiveness of exercise therapy with respect to pain reduction, while there is conflicting evidence with respect to functional improvement.

So researchers based in the Netherlands investigated the effectiveness of supervised exercise therapy compared with usual care in 131 patients aged between 14 and 40 years with patellofemoral pain syndrome.

A total of 131 participants were included in the study, 65 to a supervised exercise program (intervention group) and 66 to usual care (control group). Both groups received similar written information about the syndrome and similar instructions for home exercises, as well as advice to refrain from painful activities.

Patients rated their recovery, pain at rest, pain on activity, and function scores at the start of the study and again at three and 12 months.

After three months, the intervention group reported significantly less pain and better function than the control group. At 12 months, the intervention group continued to show better outcomes than the control group with regard to pain at rest and pain on activity, but not function.

A higher proportion of patients in the exercise group than in the control group reported recovery (42% v 35% at three months and 62% v 51% at 12 months), but these results were not significantly different between the two groups.

This study provides evidence that supervised exercise therapy for patellofemoral pain syndrome in general practice is more effective than usual care for pain at rest, pain on activity, and function at three and 12 months, say the authors. However, supervised exercise therapy had no effect on perceived recovery.

Further research is needed to understand how exercise therapy results in better outcome, they conclude.

ScienceDaily (Oct. 20, 2009)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science new's for health and building lean muscle - monthly update
« Odgovor #3 poslato: Novembar 11, 2009, 01:59:06 pre podne »
Breeding Better Broccoli: Research Points To Pumped Up Lutein Levels In Broccoli


Carotenoids -- fat-soluble plant compounds found in some vegetables -- are essential to the human diet and reportedly offer important health benefits to consumers. Plant carotenoids are the most important source of vitamin A in the human diet; the carotenoids lutein and zeaxanthin, found in corn and leafy greens vegetable such as kale, broccoli, and spinach, are widely considered to be valuable antioxidants capable of protecting humans from chronic diseases including age-related macular degeneration, cancer, and cardiovascular disease.

Vegetables in the cabbage family (such as kale, cauliflower, and broccoli) have long been known as especially good sources of dietary carotenoids. Recently, broccoli has emerged as the stand-out member of the species, providing more carotenoids to American consumers than any of its cabbage-family relatives. Yet, little has been understood about the carotenoid make-up of this popular green vegetable -- until now.

Mark W. Farnham of the U.S. Department of Agriculture, Agricultural Research Service, Charleston, South Carolina, and Dean A. Kopsell from the Plant Sciences Department, University of Tennessee, Knoxville, designed a research study aimed at finding out more about the carotenoid content of field-grown broccoli and determining the effects of genetics and the environment on carotenoid levels. The duo's research confirmed that broccoli heads contain abundant levels of lutein, an antioxidant commonly thought to provide nutritional support to eyes and skin. Other carotenoids like beta-carotene, violaxanthin, neoxanthin, and antheraxanthin were also found in broccoli heads, but lutein was clearly the most significant, accounting for about half of all carotenoids measured.

The researchers also discovered that when it comes to breeding broccoli, lutein levels were linked to the plants' genetics; the environment in which the vegetables were grown had little effect on carotenoid production.

The full study, published in a recent issue of HortScience, includes recommendations for vegetable breeders interested in producing vegetables that feature higher lutein levels. "Ultimately," reported Farnham and Kopsell, "this research indicates that breeding cultivars with increased levels of this particular carotenoid may be feasible."

ScienceDaily (Nov. 8, 2009)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science new's for health and building lean muscle - monthly update
« Odgovor #4 poslato: Novembar 11, 2009, 02:04:00 pre podne »
Cardiovascular Benefits Of Omega-3 Fatty Acids Reviewed

 Thousands of research studies have documented how the oils known as omega-3 fatty acids can benefit the cardiovascular system, particularly among people diagnosed with coronary artery disease. The incredible volume of research on this topic creates difficulty for many physicians and patients to stay current with findings and recommendations related to these oils. In the March issue of Mayo Clinic Proceedings, contributors briefly summarize current scientific data on omega-3 fatty acids and cardiovascular health, focusing on who benefits most from their protective effects, recommended guidelines for administration and dosing, and possible adverse effects associated with their use.

Two omega-3 fatty acids that have been associated with cardiovascular benefit, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), are found in fish oils. The best source for DHA and EPA are fatty coldwater fish such as herring, mackerel, salmon and tuna. Fish oil supplements or algae supplements also can provide omega-3 fatty acids.

Author James O'Keefe, M.D., a cardiologist from the Mid America Heart Institute in Kansas City, Mo., cites the results of several large trials that demonstrated the positive benefits associated with omega-3 fatty acids, either from oily fish or fish oil capsules.

"The most compelling evidence for the cardiovascular benefit provided by omega-3 fatty acids comes from three large controlled trials of 32,000 participants randomized to receive omega-3 fatty acid supplements containing DHA and EPA or to act as controls," explains Dr. O'Keefe. "These trials showed reductions in cardiovascular events of 19 percent to 45 percent. Overall, these findings suggest that intake of omega-3 fatty acids, whether from dietary sources or fish oil supplements, should be increased, especially in those with or at risk for coronary artery disease."

How much fish oil should people attempt to incorporate into their diets? According to Dr. O'Keefe, people with known coronary artery disease should consume about 1 gram per day, while people without disease should consume at least 500 milligrams (mg) per day.

"Patients with high triglyceride levels can benefit from treatment with 3 to 4 grams daily of DHA and EPA," says Dr. O'Keefe. "Research shows that this dosage lowers triglyceride levels by 20 to 50 percent."

About two meals of oily fish can provide 400 to 500 mg of DHA and EPA, so patients who need to consume higher levels of these fatty-acids may choose to use fish oil supplements to reach these targets.

Dr. O'Keefe also notes that research supports the effectiveness of combining the consumption of fish oil with the use of cholesterol-lowering medications called statins. Combination therapy with omega-3 fatty acids and a statin is a safe and effective way to improve lipid levels and cardiovascular health beyond the benefits provided by statin therapy alone. Blood DHA and EPA levels could one day be used to identify patients with deficient levels and to individualize therapeutic recommendations.

Dr. O'Keefe found little evidence of serious adverse effects associated with fish oil consumption. "In prospective placebo-controlled trials, no adverse effects were observed to occur at a frequency of more than 5 percent, and no difference in frequency was noted between the placebo and omega-3 fatty acid groups," he says.

The most commonly observed side effects include nausea, upset stomach and a "fishy burp." Taking the supplement at bedtime or with meals, keeping fish oil capsules in the freezer or using enteric-coated supplements may help reduce burping and upset stomach symptoms.

ScienceDaily (Mar. 12, 2008)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science new's for health and building lean muscle - monthly update
« Odgovor #5 poslato: Novembar 12, 2009, 10:49:58 posle podne »
Alcohol retards athletic performance says study


Even moderate amounts of alcohol slows down recovery from athletic performance, besides doubling muscle performance loss, a new study has found. “If you’re there to perform, you shouldn’t be drinking alcohol,” said Matt Barnes, author of the study.

Barnes, B.Sc Honours candidate at the Massey University’s Manawatu campus, recruited recreational sportsmen and tested their muscle performance after a strenuous resistance training session, followed by either a moderate amount of alcohol in juice or the same energy content in juice alone.

Using specialised equipment at the Institute of Food, Nutrition and Human Health, the athletes’ performance was measured at 36-hours and 60 hours later.

“That’s two mornings and three mornings later,” Barnes said. “With the alcohol the loss of muscle performance was far greater - nearly twice as much. Normally you would expect to see weakness or loss in performance after strenuous exercise but thealcohol really exacerbated that.

“This shows that if you drink even moderate levels of alcohol after you use your muscles strenuously you are impairing your ability to recover and I would say if you are serious about your sport, you shouldn’t be drinkingalcohol in the post-match or recovery period.”

Exercise physiologist and co-director of Sport and Exercise Science at Massey University Steve Stannard is supervising Barnes’ research. Stannard said he began thinking of undertaking research on the effect ofalcohol on athletic performance after organising a sport and alcohol conference in 2005.

“It struck me at the time that, whilst alcohol was commonly consumed after competition, there was very little research on whether alcohol affected the recovery process,” according to a Massey release.

“Although many sportspeople drink, rugby is the most obvious: they go after training or the match to the pub or club to socialise or celebrate. In fact some coaches encourage that - I’ve even been told matter-of-factly by a high profile coach that ‘the spirit of the team is at the bottom of the bottle’,” said Stannard.


January 15th, 2009 (IANS)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #6 poslato: Novembar 12, 2009, 10:55:03 posle podne »
Strength training and aerobic exercise help reduce cardiovascular risks & pain


Strength training helps lower heart disease and stroke risk factors, while all-around exercise reduces neck and shoulder pain, suggests a new study.

Lead researcher Dr. Mogens T. Pedersen, of the University of Copenhagen, says that strength training and all-around exercise are a valuable part of work site exercise programs that have multiple benefits.

During the study, the researchers randomly assigned 841 Danish employees to two exercise groups.

One group did all-around exercise like aerobics and walking, while the other focused on strength training, particularly on the shoulder and cervical spine (neck) muscles.

A third group received no exercise program at work.

The researchers found reductions in cardiovascular risk factors, including blood pressure and body fat, in not only those assigned to aerobic exercise, but also in those who did strength training.

The average reduction in blood pressure was big enough to lead to a 25 percent reduction in stroke risk.

Both types of physical activity also reduced back and shoulder pain by nearly 30 percent, when compared to the no-exercise group.

Dr. Pedersen and colleagues write: “These positive health-related adaptations occurred in spite of relatively small changes in physical capacity.”

The study has been published in the Journal of Occupational and Environmental Medicine.

July 11th, 2009 (ANI)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #7 poslato: Novembar 12, 2009, 11:55:12 posle podne »
Nandrolone Could Cause Liver Problems

Most bodybuilders are well aware that oral anabolic steroids are toxic to the liver. So, many use injectable drugs such as nandrolone because they feel they are more liver-friendly. Brazilian researchers, in a study on rats, found that low, normal and high doses of nandrolone administered for five weeks increased key liver enzymes (aspartate aminotransferase, AST; alanine aminotransferase, ALT; and alkaline phosphatase, ALP). Changes were highest in the high-dose group, but liver function tests remained within the normal range in all groups. The authors concluded that administering higher than clinical doses could damage the liver. There are no long-term studies showing the effects of nandrolone or any other anabolic steroid on liver function.

(Medicine Science Sports Exercise, 40: 842-847, 2008)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #8 poslato: Novembar 13, 2009, 12:21:33 pre podne »
Intense Exercise Suppresses The Immune System

The purpose of weight training or any other kind of exercise is to stress the body so that it adapts and get stronger and improves its fitness. Too much exercise can backfire, resulting in overuse injuries, overtraining and suppression of the immune system. Serious bodybuilders almost all live by the motto that “more is better and you can’t work too hard.” Unfortunately, overwork can cause major setbacks that can delay progress many months. Japanese researchers, in a study on rats, showed that four consecutive days of treadmill running to exhaustion suppressed the immune system. Compared to a control group, the overtrained rats experienced decreases in blood levels of immunoglobulin A, which is important for fighting off bacteria and viruses that cause colds, flu and other diseases. The researchers measured immunoglobulins in the saliva and suggested that this method might be appropriate for detecting overtraining in adult athletes.

(Scandinavian Journal Medicine Science Sports, 18: 367-372, 2008)

---------------------------------------------------------------

Weight Training And Timed Essential Amino Acids Prevent Muscle Loss During Bed Rest

Extended periods of weightlessness in space causes severe tissue wasting that interferes with performance during the missions and causes long-term health problems. Scientists use bed rest to simulate the effects of weightlessness. Typically, test subjects lie in bed for 20 or more days at a time and are not allowed to sit up. This can decrease physical capacity by up to 25 percent in a relatively short time. A Tufts University study found that combining resistance training with amino acid supplementation reduced physical deterioration by 66 percent during a 28-day bed rest study that included a low-calorie diet. Mid-thigh muscle area decreased 11 percent In Control subjects but only 3 percent in subjects who weight-trained and took the supplements. This study showed the value of weight training and supplemental Amino Acids for preventing physical deterioration during bed rest and perhaps weightlessness, aging and the rigors of cutting up for a bodybuilding contest.

(Journal of Applied Physiology, in press; published online May 18, 2008)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #9 poslato: Novembar 13, 2009, 12:47:01 pre podne »
Periodization Of Training Speeds Gains In Strength And Size

Periodization of training varies the exercises, volume and intensity of workouts during different times of the year and from one workout to the next. Periodization promotes the development of base strength, peak strength, general conditioning and recovery. Forty years ago, most American athletes trained as hard as they could in almost every workout. This led to overtraining and overuse injuries. Periodization of training was popularized in the Eastern Bloc countries, such as the Soviet Union and East Germany. The technique gradually made its way to the West and has been an important part of our training methods since the early 1980s. Athletes have used periodization for many years, but we have few published studies on the technique. Most of our information is based on trial-and-error observations by athletes and coaches. Researchers from Texas Woman’s University and the National Strength and Conditioning Association said that we need more long-term studies to help us understand periodization of training. These studies should involve observations and surveys, so that the research is more applicable to real world athletics.

(Strength Conditioning Journal, 30: 45-51, 2008)


----------------------------------------------------------


Leptin Plus Exercise Promotes Weight Loss

In 1995, scientists reported the remarkable effects of a hormone called leptin on weight loss. Genetically obese mice injected with leptin lost 20 percent of their bodyweight in only a few weeks. Scientists thought they discovered the magic bullet for weight control. The body uses leptin to maintain a constant weight. It works by decreasing appetite and increasing metabolic rate when you overeat. Surprisingly, obese people have more leptin than lean people. Overweight people become leptin insensitive, so the hormone stops working. Leptin might help people lose weight after all. Researchers From the University of Florida found that combining leptin with a small amount of exercise promoted weight loss better than exercise or leptin alone. Exercise acts as a metabolic signal that allows leptin to increase metabolic rate and depress appetite. The combination of leptin and exercise is promising, but experimental.

(Diabetes, 57: 614-622, 2008)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #10 poslato: Novembar 19, 2009, 08:42:37 posle podne »
Runners: Train Less and Be Faster

In a recent scientific study just published in the Journal of Applied Physiology, Bangsbo and co-workers demonstrate that by reducing the volume of training by 25% and introducing the so-called speed endurance training (6-12 30-s sprint runs 3-4 times a week), endurance trained runners can improve not only short-term but also long-term performance.

Thus, the runners improved their 10-km time by 1 min from 37.3 to 36.3 min after just 6-9 weeks of changed training. Six of the participating 12 runners obtained a new personal record on the 10-km, despite having been training for more than 4 years. The most impressive achievement was the one runner who lowered the time with more than 2 minutes from 37.5 til 35.4 min. In addition, performance in a 30-s sprint test and an intense exhaustive run (about 2 minutes) was improved by 7% and 36%, respectively. In agreement, the authors have previously shown that an 85% reduction in training volume can improve short-term performance (see right column).

In association with the improved performance the amount of muscle Na+/K+ pumps was elevated and the rate of accumulation of potassium during exercise was lowered, and it is speculated that this may play a significant role for the increased performance.

ScienceDaily (Nov. 15, 2009)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #11 poslato: Novembar 21, 2009, 12:22:41 pre podne »
Four Weeks of Ketosis Diet in Trained Athletes

To study the effect of chronic ketosis on exercise performance in endurance-trained humans, five well-trained cyclists were fed a eucaloric balanced diet (EBD) for one week providing 35-50 kcal/kg/d, 1.75 g protein/kg/d and the remainder of kilocalories as two-thirds carbohydrate (CHO) and one-third fat. This was followed by four weeks of a eucaloric ketogenic diet (EKD), isocaloric and isonitrogenous with the EBD but providing less than 20 g CHO daily. Both diets were appropriately supplemented to meet the recommended daily allowances for vitamins and minerals. Pedal ergometer testing of maximal oxygen uptake (VO2max) was unchanged between the control week (EBD-1) and week 3 of the ketogenic diet (EKD-3). The mean ergometer endurance time for continuous exercise to exhaustion (ENDUR) at 62%-64% of VO2max was 147 minutes at EBD-1 and 151 minutes at EKD-4. The ENDUR steady-state RQ dropped from 0.83 to 0.72 (P less than 0.01) from EBD-1 to EKD-4. In agreement with this were a three-fold drop in glucose oxidation (from 15.1 to 5.1 mg/kg/min, P less than 0.05) and a four-fold reduction in muscle glycogen use (0.61 to 0.13 mmol/kg/min, P less than 0.01). Neither clinical nor biochemical evidence of hypoglycemia was observed during ENDUR at EKD-4. These results indicate that aerobic endurance exercise by well-trained cyclists was not compromised by four weeks of ketosis. This was accomplished by a dramatic physiologic adaptation that conserved limited carbohydrate stores (both glucose and muscle glycogen) and made fat the predominant muscle substrate at this submaximal power level.

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #12 poslato: Decembar 13, 2009, 12:56:20 pre podne »
Stretching Decreases Muscle Strength Power

Pre-exercise stretching was once part of the normal warm-up ritual of almost all strength, power and endurance athletes. Most fitness experts said that stretching increased muscle and joint range of motion, which made movements easier and reduced the risk of injury. It turns out that pre-exercise stretching is a bad idea that decreases performance and increases the risk of injury. Pre-exercise stretching reduces muscle strength and power and interferes with the brain’s ability to control the muscles. Greek researchers found that muscle power decreases the longer you stretch the muscle. They measured the effects of stretches lasting from 10 seconds to 60 seconds on isometric strength and power. Stretching for 30 seconds decreased isometric strength by nearly 9 percent, while stretching 60 seconds decreased power by 16 percent. Stretching 30 seconds or longer has similar effects in decreasing muscle power. They recommended that athletes avoid static stretching of muscles for 30 seconds or more before activities requiring maximum strength and power.

(Journal Strength Conditioning Research, 22: 40–46, 2008)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #13 poslato: Decembar 13, 2009, 01:01:33 pre podne »
Training To Failure: How Much And How Often?

Feeling the burn and pushing reps to the max have always been part of effective training for bodybuilding. Failure training involves doing an exercise until the muscles no longer respond. Jeff Willardson from Eastern Illinois University discussed the pluses and minuses of failure training methods. Many studies have examined the optimal number of sets in a program, but few have looked at the effects of failure training on muscle size and strength. Failure training allows advanced bodybuilders and lifters to break training plateaus and move to the next level. These highly intense workouts must be incorporated into short-term cycles to avoid overtraining. Failure training is effective, because it recruits more motor units (muscle fibers and their nerve supply) and stimulates the secretion of anabolic hormones such as growth hormone, insulin-like growth factor and testosterone and increases insulin sensitivity (insulin is a powerful anabolic hormone). Increases in strength require high-intensity overload, so bodybuilders should not rely on high-rep burn programs for making progress. Bodybuilders and power athletes must push the big iron if they want to get strong and big. Excessive failure training leads to injury, overtraining and loss of motivation. Failure training can move you to the next level, but don’t overdo it.

(Journal Strength Conditioning Research,21: 628–631, 2007)

Van mreže The_Bulldog

  • Super-heavyweight Member
  • ******
  • Poruke: 3.349
Odg: Science news for health and building lean muscle - monthly update
« Odgovor #14 poslato: Decembar 13, 2009, 01:10:35 pre podne »
Cardio Protects Blood Vessels from Harmful Effects of Weight Training

Weight training increases muscle and bone mass and has positive effects on metabolism. It can, however, stress the blood vessels. At rest the average blood pressure is about 100 millimeters of mercury (mmHg.). Peak systolic blood pressure (higher blood pressure number) during heavy squats is as high as 400 mmHg. A single weight-training workout stiffens
the blood vessels, which could gradually damage the cells lining the vessels and stress the heart. Cardio on the other hand, makes the vessels more compliant and enhances their health and function. Japanese researchers found that doing cardio exercise after weight training promoted blood vessel health and compensated for the negative effects of weight training on blood vessel stiffness. Doing cardio before weight training did not provide a protective effect. Performing cardio after weight training benefits blood vessels and maximizes the training effects of resistive exercise, because you can lift more intensely with less fatigue.

(Journal Applied Physiology, 103:1655–1661, 2007)